// Copyright 2016 The Draco Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#ifndef DRACO_COMPRESSION_ATTRIBUTES_MESH_ATTRIBUTE_INDICES_ENCODING_OBSERVER_H_
#define DRACO_COMPRESSION_ATTRIBUTES_MESH_ATTRIBUTE_INDICES_ENCODING_OBSERVER_H_

#include "draco/compression/attributes/mesh_attribute_indices_encoding_data.h"
#include "draco/compression/attributes/points_sequencer.h"
#include "draco/mesh/mesh.h"

namespace draco {

// Class that can be used to generate encoding (and decoding) order of attribute
// values based on the traversal of the encoded mesh. The class should be used
// as the TraversalObserverT member of a Traverser class such as the
// EdgeBreakerTraverser (edgebreaker_traverser.h).
template <class CornerTableT>
class MeshAttributeIndicesEncodingObserver {
  public:
    MeshAttributeIndicesEncodingObserver()
        : att_connectivity_(nullptr),
          encoding_data_(nullptr),
          mesh_(nullptr),
          sequencer_(nullptr) {}
    MeshAttributeIndicesEncodingObserver(
        const CornerTableT *connectivity, const Mesh *mesh,
        PointsSequencer *sequencer,
        MeshAttributeIndicesEncodingData *encoding_data)
        : att_connectivity_(connectivity),
          encoding_data_(encoding_data),
          mesh_(mesh),
          sequencer_(sequencer) {}

    // Interface for TraversalObserverT

    void OnNewFaceVisited(FaceIndex /* face */) {}

    inline void OnNewVertexVisited(VertexIndex vertex, CornerIndex corner) {
        const PointIndex point_id =
            mesh_->face(FaceIndex(corner.value() / 3))[corner.value() % 3];
        // Append the visited attribute to the encoding order.
        sequencer_->AddPointId(point_id);

        // Keep track of visited corners.
        encoding_data_->encoded_attribute_value_index_to_corner_map.push_back(
            corner);

        encoding_data_
        ->vertex_to_encoded_attribute_value_index_map[vertex.value()] =
            encoding_data_->num_values;

        encoding_data_->num_values++;
    }

  private:
    const CornerTableT *att_connectivity_;
    MeshAttributeIndicesEncodingData *encoding_data_;
    const Mesh *mesh_;
    PointsSequencer *sequencer_;
};

}  // namespace draco

#endif  // DRACO_COMPRESSION_ATTRIBUTES_MESH_ATTRIBUTE_INDICES_ENCODING_OBSERVER_H_
